Whites Surf PI schematic

[ashkelon]

I do not recognize this board can you show the schematic?

mostly all of their same schema

[DOOLEY]

hello Ashkelon,

EARTH MAGNETIC FIELD is everywhere................ ( even inside house !! )



in your last video, that is most DEFINITELY earth magnetic field you are seeing.

going to guess your testing at the output of the pre-amp ??
this is normal.

magnetic field effect on the base line is REDUCED after the C4 / R12 filter.

it's the following stage ( 4066 sample switches and integrator that remove the earth field )
( hopefully....... )

[ashkelon]

hello Ashkelon,

EARTH MAGNETIC FIELD is everywhere................ ( even inside house !! )



in your last video, that is most DEFINITELY earth magnetic field you are seeing.

going to guess your testing at the output of the pre-amp ??
this is normal.

magnetic field effect on the base line is REDUCED after the C4 / R12 filter.

it's the following stage ( 4066 sample switches and integrator that remove the earth field )
( hopefully....... )

Thanks Dooley, Must i replace the bigger value r12 = 20K c4 = 200N ?

[DOOLEY]

hello Ashkelon,

NO.........
values of C4 / R12 are just fine,

experimented with changing the values in the past,
and,
although not TO critical, 10k and 100nf seen to work the best.


as I said, base line fluctuation at the pre-amp output is normal,
earth field removed by the next stage.

measure D.C level at the output of the op-amp on the next stage,
earth field, or small non metallic magnet should have NO ( or little ) effect.

however,
nearby interference may still be there.

indoor environments can be electrically quite noisy.

mains electric, fridge motors, florescent lights, battery clocks ( esp these !! dam you battery clocks !! ) LOL.

[eclipse]

hello Ashkelon,

NO.........
values of C4 / R12 are just fine,

experimented with changing the values in the past,
and,
although not TO critical, 10k and 100nf seen to work the best.

Some schematics use 10uF/20uF (ESR < 0.05R) cap and 100K resistor.
You can try these values if you feel like experimenting, although guys will say electrolytic cap is source if noise

[cagatelorito]

Good morning and cordial greetings,
I´m new in this foro and I have a little question, there are many schematics, pcb´s, modifications and discussions about Surf Pi but is very dificult to find which is good, best or ultimate...can someone tell me the most advisable option?
Thanks !!!

[württemberger]

This was my build...

[cagatelorito]

Please, I need a little help,
how do I adjust R10 without osciloscope? What is the value?
Thanks

[homefire]

This should help.

[cagatelorito]

Thanks!!!

This should help.

[cagatelorito]

Please another question, I got to start the surfmaster and it detects a coin of euro next 25-28 cm, and ring of gold 12-14 cm, I think its good but if I keep de coin when it is beep and don´t move it after 2 or 3 seconds stop beeping and is necessary to move again, that is normal?...

[homefire]

Yes it's a motion detector. I think there was a mod to fix that.

[cagatelorito]

Thanks again!!!

[chemelec]

Yes it's a motion detector. I think there was a mod to fix that.

Why do most of the Kits available for this, Don't have the GAIN CONTROL.
Is it Not useful?



ALSO, I HAVE TRIED THIS, BUT IT DOESN'T SEEM TO MAKE ANY DIFFERENCE

[homefire]

Easy Enough to do. Replace the Feedback Resistor 1M on NE5534 to a Pot.

Not tried the Motion no Motion mod. It didn't keep the Threshold Tone going any longer ?